1. Field of the Invention
The present invention relates to an apparatus and method for fabricating an organic light emitting diode display device, and more particularly, to an apparatus and method for fabricating an organic light emitting diode display device capable of depositing a layer on a substrate to fabricate the organic light emitting diode display device.
2. Description of the Related Art
In general, in order to solve problems of conventional display devices such as cathode ray tubes, and so on, flat panel displays have been developed and released. Such flat panel displays may be classified into a liquid crystal display, an organic light emitting diode display device, a plasma display panel (PDP), and so on.
Among the flat panel displays, the organic light emitting diode display device has advantages such as a small thickness, rapid response, simple manufacture, and low cost. Therefore, in recent times, the organic light emitting diode display device has been widely used as one of the flat panel displays.
Meanwhile, flat panel displays have become larger. Therefore, the organic light emitting diode display device has also become larger with the increase in size of the flat panel displays. However, the large size of the flat panel displays has brought various new problems. For example, a method of fabricating an organic light emitting diode display device includes depositing a layer having a certain pattern on a substrate formed of glass. At this time, the layer deposition process is performed by attaching a mask having a predetermined pattern of openings to the lower surface of the substrate, and then evaporating a predetermined deposition material such as an organic material, an electrode material, and so on, from under the mask toward the mask. Therefore, the evaporated deposition material is deposited on the substrate through the openings of the mask to form a layer having a certain pattern on the substrate.
However, since the large size of the flat panel displays requires the use of a larger size substrate having the layer formed thereon and a larger size mask adhering to the substrate, for example, a central area of the substrate and the mask adhering to the substrate may be sagged.
Therefore, a portion of the mask may not completely contact the lower surface of the substrate due to the sagging. As a result, a predetermined size of space, i.e., a loosened space is formed between the portions of the substrate and the mask. Therefore, the deposition material evaporated toward the mask is deposited into the space, which causes degradation of the pattern layer formed on the substrate.
Japanese Patent Laid-open Publication No. H10-41069, “Method of Fabricating Organic Light Emitting Diode Display Device,” published on Feb. 13, 1998, discloses a method of attaching a mask to a substrate. According to the above publication, a mask is disposed at one surface of the substrate, and a magnetic field source is disposed at the other side of the substrate opposite the one surface such that the mask is attracted by the magnetic field. Therefore, the mask adheres to the substrate by the magnetic field generated from the magnetic field source.
However, when the substrate and the mask adhering thereto become larger, the above method also causes new problems. That is, when the substrate and the mask become larger, for example, a center area of a portion of the substrate and the mask adhering to the mask may be sagged downward. Even when the sagging occurs, the magnetic field source generates a strong enough magnetic field by which the mask is adhering to the substrate. However, the strong magnetic field distorts the mask, which should adhere to the substrate, causing degradation of the pattern layer formed on the substrate.